Light mixing and homogenizing apparatus and method

ABSTRACT

In accordance with one embodiment, a light mixing and homogenizing apparatus includes a first tubular member and a second tubular member. The first tubular member has a reflective interior surface, a polygonal cross section with a first maximum diameter, and a first number of sides. The first tubular member has a first end and a second end with the first end configured to receive a plurality of incoming light beams. The second tubular member has a reflective interior surface, a polygonal cross section with a second maximum diameter smaller than the first maximum diameter, and a second number of sides that is different from the first number of sides. The second tubular member has a first end disposed adjacent to a first tubular member second end. The second tubular member second end is configured to output a homogeneous light beam comprising a mixture of the plurality of incoming light beams.

TECHNICAL FIELD

The present invention relates generally to optical guides, and moreparticularly to an optical apparatus for mixing and homogenizing aplurality of input light beams and producing a uniform intensity output.

RELATED ART

Optical devices to mix two or more incoming light beams are known, yetsuch devices typically include heavy, expensive, and delicate componentswhich limit the application of this useful technique. Further, since theincoming light beams typically have a Gaussian, non-uniform intensitydistribution, additional components are typically required to produce auniform intensity distribution. Such additional components contribute tothe increased cost and weight of the optical system. Thus, there remainsa need for an apparatus and method to produce a mixed and homogenizedoutput light beam from a plurality of non-homogenous incoming lightbeams in a rugged, compact, and low cost manner.

SUMMARY

Apparatuses, systems, and methods are disclosed herein to provide lightmixing and homogenization of a plurality of incoming light beams. Forexample, in accordance with an embodiment of the present invention, alight mixing and homogenizing apparatus includes a first tubular memberand a second tubular member. The first tubular member has a reflectiveinterior surface and a polygonal cross section with a first maximumdiameter and a first number of sides. The first tubular member has afirst end and a second end with the first tubular member first endconfigured to receive a plurality of incoming light beams. The secondtubular member has a reflective interior surface and a polygonal crosssection with a second maximum diameter smaller than the first maximumdiameter, and a second number of sides different from the first numberof sides. The second tubular member has a first end disposed adjacent tothe first tubular member second end. The second tubular member has asecond end configured to output a homogeneous light beam comprising amixture of the plurality of incoming light beams.

According to another embodiment, a light mixing and homogenizing systemincludes a plurality of light sources, a tubular body, and a dividerlocated within a first portion of the tubular body. Each light sourceprovides a light beam having a unique wavelength. The tubular body has afirst end portion with a square cross section and a second end portionwith a hexagonal cross section. The first end portion is configured toreceive the plurality of light beams. The tubular body second endportion is configured to output a homogeneous light beam including amixture of the incoming light beams. An interior portion of the tubularbody has a highly reflective surface configured to reflect light fromthe plurality of incoming light beams causing a mixing and homogenizingof the plurality of light beams. The divider is located within thetubular body first end portion and is configured to separate theincoming light beams prior to mixing.

According to yet another embodiment of the present invention, a methodof mixing and homogenizing a plurality of light beams includes theoperations of receiving the light beams into a divided first portion ofan optical funnel, mixing the received light beams within an undividedsecond portion of the optical funnel to produce a mixed light beam,homogenizing the mixed light beam to produce a homogenized light beamhaving a substantially equal intensity distribution in a directionperpendicular to the path of the homogenized beam, and outputting thehomogenized beam.

The present disclosure teaches structures and methods that fulfill longfelt needs in the industry by producing a mixed and homogenized lightbeam from a plurality of incoming light beams, where each of theincoming light beams has a non-uniform, gaussian intensity distribution.In particular, the structures and methods disclosed have particularapplication to diverse technology areas including optical components,entertainment, automotive, and mass communications. The disclosedstructure is beneficial because it does not include a traditional,filled optical cavity or optical components such as beam splitters, andthus may be manufactured more economically. Additionally, the disclosedstructure is rugged and may be used in applications that may receivephysical shock. Since no additional optical components are needed,alignment issues are eliminated.

The scope of the present invention is defined by the claims, which areincorporated into this section by reference. A more completeunderstanding of embodiments of the present invention will be affordedto those skilled in the art, as well as a realization of additionaladvantages thereof, by a consideration of the following detaileddescription. Reference will be made to the appended sheets of drawingsthat will first be described briefly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a first perspective view of the light mixing andhomogenizing apparatus with the divider member inserted along thelongitudinal axis in accordance with an embodiment.

FIG. 2 shows a second perspective view of the light mixing andhomogenizing apparatus with the divider removed in accordance with anembodiment.

FIG. 3 shows a side view of the light mixing and homogenizing apparatusin accordance with an embodiment.

FIG. 4 shows an end view of tubular body as viewed from the first end offirst tubular member where first tubular member is a regular, squarepolygon having equal length sides while second tubular member is not aregular, hexagonal polygon, in accordance with an embodiment.

FIG. 5 shows and end view of tubular body as viewed from the first endof first tubular member where first tubular member is a regular, squarepolygon having equal length sides while second tubular member is aregular, hexagonal polygon, also having equal length sides, inaccordance with an embodiment.

FIG. 6 shows and end view of tubular body as viewed from the first endof first tubular member where first tubular member is not a regular,square polygon yet still has equal length sides, while second tubularmember is a regular, hexagonal polygon having equal length sides.

FIG. 7 shows a flow diagram indicating operations for a method of usinga light mixing and homogenizing apparatus, in accordance with anembodiment.

FIG. 8 shows a block diagram of a light mixing and homogenizing systemthat includes a plurality of light sources, a control unit, and a lightmixing and homogenizing apparatus, in accordance with an embodiment.

FIG. 9 shows an example of light intensity from a single optical fiberoutput where the light intensity profile varies across the diameter, ina direction perpendicular to the cross section of the fiber, with atypical Gaussian intensity distribution.

FIG. 10 shows an example of light output from the light mixing andhomogenizing apparatus producing a uniform intensity across the span ofthe tubular body output, with a typical top-hat intensity distribution.

FIG. 11 shows a plurality of incoming light sources producing aplurality of incoming light beams that are applied to a wider input as areceiving end of the light mixing and homogenizing apparatus.

FIG. 12 shows the plurality of incoming light sources located within areceiving portion of the tubular body.

FIG. 13 shows the ends of each light source as inserted within thetubular body first end portion.

Embodiments of the present invention and their advantages are bestunderstood by referring to the detailed description that follows. Itshould be appreciated that like reference numerals are used to identifylike elements illustrated in one or more of the figures.

DETAILED DESCRIPTION

In reference to FIG. 1, an embodiment of a light mixing and homogenizingapparatus 100 includes a tubular body 102 having a first end portion ortubular member 104 with a square cross-section and a second end portionor tubular member 106 with a hexagonal cross-section. Both first endportion 104 and second end portion 106 are arranged about a central,longitudinal axis 108 so that the geometric cross-section for each endportion (104, 106) extends symmetrically in the direction oflongitudinal axis 108 forming sides of the end portions.

In this disclosure, longitudinal axis 108 can include a central linepassing symmetrically through the long or axial direction of tubularbody 102 equidistant from each side member in first end portion 104 andsecond end portion 106. First end portion 104 can receive a plurality ofincoming light beams (110, 112, 114, 116), each incoming light beam hasa Gaussian distribution where the intensity at the center of theincoming beam is higher than near the edges. A dividing member 118separates incoming light beams (110, 112, 114, 116) prior to mixing andtypically extends the entire length of first portion 104.

The received light beams are mixed by reflection off a highly reflectiveinterior surface of tubular body 102 so that second end portion 106outputs a mixed, homogenized light beam 120 having a color determined bythe intensity and wavelength of each incoming light beam. Any or all ofincoming light beams (110, 112, 114, and 116) may be either coherentbeams comprising a single wavelength of light, or incoherent beamscomprising multiple wavelengths. In this disclosure, a plurality oflight beams are mixed when a composite light beam is formed havingwavelength components from each of the plurality light beams. Similarly,a mixed light beam is homogenized when the mixed light beam has asubstantially equal intensity distribution in a direction perpendicularto the output beam path.

FIG. 2 shows dividing member 118 removed from first end 104 of tubularbody 102. A middle portion 202 of tubular body 102 includes a pluralityof angled planes joining the different polygonal shapes of first endportion 104 and second end portion 106, and where each of the incominglight beams is initially reflected. A small portion of light from theincoming light beams may pass through the center portion of tubular body102 without being reflected from the internal surface and withoutdisturbing the homogenous intensity profile. Even though asquare-to-hexagonal shaped transition is shown in this disclosure, othergeometrical cross-sections may be used for both first end section 104and second end section 106 so that middle portion 202 comprises aplurality of planar members that join first end portion 104 to secondend portion 106.

FIG. 3 shows a side view of light mixing and homogenizing apparatus 100including first end portion 104, second end portion 106, and middleportion 202 for joining or mating first end portion 104 and second endportion 106. In one embodiment, first end portion 104 includes a firstsquare side member 302 and a second square side member 304 where eachsquare side (302, 304) has a planar outer surface extending alonglongitudinal axis 108 to form the sides of square first end portion 104.The geometrical cross-section of first end portion 104 determines thenumber of sides, where a square cross-section has four sides. At thejuncture between square side 302 and square side 304 is an edge 306 thatruns parallel to longitudinal axis 108. Similarly, at the juncturebetween square side 302 and an adjoining square side (not shown) in adirection away from square side 304 is an edge 308 that runs parallel tolongitudinal axis 108.

Finally, at the juncture between square side 304 and an adjoining squareside (not shown) in a direction away from square side 302 is an edge 310that runs parallel to longitudinal axis 108. In this manner, thepolygonal cross-section of first end portion 104 extends in thedirection of longitudinal axis 108 in order to form a hollow, squarestructure with a diagonal opening maximum opening width W₁ 312corresponding to a maximum diameter of the first end portion 104.Measured at the corners of first end portion 104, W₁ represents thelargest opening width. The inner surfaces of first portion 104 arehighly reflective in order to reflect light within tubular body 102. Inone embodiment, the width of the surface of each square side (302, 304)is 1.931 cm as measured perpendicular to longitudinal axis 108. Themaximum width W₁ 312 is dependent upon the length of tubular body 102.

Second end portion 106 includes a first hexagonal side member 314, asecond hexagonal side member 316, and a third hexagonal side member 318where each hexagonal side (314, 316, 318) has a planar outer surfaceextending along longitudinal axis 108 to form the sides of hexagonalsecond end portion 106. The geometrical cross-section of second endportion 106 determines the number of sides, where a hexagonalcross-section has six sides. At the juncture between hexagonal side 314and hexagonal side 316 is an edge 320 that runs parallel to longitudinalaxis 108. Similarly, at the juncture between hexagonal side 316 andhexagonal side 318 is an edge 322 that runs parallel to longitudinalaxis 108. At the juncture between hexagonal side 314 and an adjoininghexagonal side (not shown) in a direction away from hexagonal side 316is an edge 324 that runs parallel to longitudinal axis 108. The line ofedge 308 and the line of edge 324 define a plane (not shown) that passesthrough the center of tubular body 102 along longitudinal axis 108.

Finally, at the juncture between hexagonal side 318 and an adjoininghexagonal side (not shown) in a direction away from hexagonal side 316is an edge 326 that runs parallel to longitudinal axis 108. The line ofedge 310 and the line of edge 326 define a plane (not shown) that passesthrough the center of tubular body 102 along longitudinal axis 108. Inthis manner, the polygonal cross-section of second end portion 106extends in the direction of longitudinal axis 108 in order to form ahollow, hexagonal structure with a maximum opening width W₂ 328corresponding to a maximum diameter of second end portion 106. The innersurfaces of second portion 106 are highly reflective in order to reflectlight within tubular body 102. In one embodiment, maximum width W₂ 328is 2.000 cm, while the minimum width measured perpendicular to opposingsides is 1.732 cm. The width measured between opposite corners of thepolygonal cross-section of second end portion 106 is equal to anon-maximum width of the polygonal cross-section of first end portion104 so that at least one longitudinal edge (320, 322) coincides with aside of first end portion 104.

Middle portion 202 includes a first triangular side member 332, a secondtriangular side member 334, a third triangular side member 336, and afourth triangular side member 338. Each triangular side (332, 334, 336,and 338) has a planar outer surface extending at an angle alonglongitudinal axis 108 to form a generally conically shaped middleportion 202 that joins the wider first portion 104 with the narrowersecond portion 106. The inner surfaces of middle portion 202 are highlyreflective in order to reflect light within tubular body 102. Lightreceived in first portion 104 is conducted through middle portion 202and exits second portion 106 so that tubular body 102 comprises a lightfunnel having a wider input 330 and a narrower output 340.

Triangular side 332 joins a first portion of square side 302 withhexagonal side 314. At the juncture between triangular side 332 andsquare side 302 is an edge 342 that runs within a plane (not shown) thatis perpendicular to longitudinal axis 108. At the juncture betweentriangular side 332 and hexagonal side 314 is an edge 344 that runs onhexagonal side 314 from edge 320 to edge 324. Finally, at the juncturebetween triangular side 332 and an adjoining triangular side (not shown)in middle portion 202 is an edge 346 that runs from square side 302 tohexagonal side 314 within the plane defined by the line of edge 308 andthe line of edge 324 that passes through the center of tubular body 102along longitudinal axis 108. Edge 346 has a slope determined by thedifference between W₁ 312 and W₂ 328. Triangular side 332 is alsobounded by a first vertex 348 where edge 342 meets edge 346, a secondvertex 350 where edge 342 meets edge 344, and a third vertex 352 whereedge 344 meets edge 346. Vertex 348 coincides with a longitudinal edge308 of square side 302, vertex 350 coincides with a longitudinal edge320 of hexagonal side 314, and vertex 352 coincides with a longitudinaledge 324 of hexagonal side 314. In this manner, the different geometriesof first portion 104 and second portion 106 are joined using an angledplanar member having vertices that coincide with longitudinal edges.

Triangular side 334 joins a second portion of square side 302 withhexagonal side 316. The juncture between triangular side 334 and thesecond portion of square side 302 is along edge 342. At the juncturebetween triangular side 334 and hexagonal side 316 is an edge 356 thatruns on hexagonal side 316 from edge 348 to a central portion ofhexagonal side 316. Triangular side 334 is adjacent to triangular side336. At the juncture between triangular side 334 and triangular side 336is an edge 358 that runs within a plane defined by the line of edge 306and the central longitudinal axis 108. Triangular side 334 is alsobounded by a first vertex 350 where edge 342 meets edges 344 and 356, asecond vertex 360 where edge 342 meets edge 358, and a third vertex 362where edge 356 meets edge 358. Edge 358 has a slope corresponding to theslope of edge 346 so that the sides are symmetrical. Vertices 360 and362 correspond to a line of longitudinal edge 308. In this manner, thedifferent geometries of first portion 104 and second portion 106 arejoined using an angled planar member having vertices that coincide withthe longitudinal edges of the geometries of at least one of first endportion 104 and second end portion 106.

Triangular side 336 joins a first portion of square side 304 withhexagonal side 316. The juncture between triangular side 336 and thefirst portion of square side 304 is along edge 366 within the planeperpendicular to longitudinal axis 108 that includes edge 342. At thejuncture between triangular side 336 and hexagonal side 316 is an edge368 that runs on hexagonal side 316 from edge 366 to a central portionof hexagonal side 316. Triangular side 336 is also bounded by a firstvertex 360 where edge 366 meets edges 358 and 342, a second vertex 370where edge 366 meets edge 368, and a third vertex 362 where edge 368meets edges 356 and 358. Vertex 370 corresponds to a line oflongitudinal edge 322. In this manner, the different geometries of firstportion 104 and second portion 106 are joined using an angled planarmember having vertices that coincide with the longitudinal edges of thegeometries of at least one of first end portion 104 and second endportion 106.

Triangular side 338 joins a second portion of square side 304 withhexagonal side 318 along edge 366. At the juncture between triangularside 338 and hexagonal side 318 is an edge 374 that runs on hexagonalside 318 from edge 322 to edge 326. Finally, at the juncture betweentriangular side 338 and an adjoining triangular side (not shown) inmiddle portion 202 in a direction away from triangular side 336 is anedge 376 that runs from square side 304 to hexagonal side 318 within theplane defined by the line of edge 310 and the line of edge 326 thatpasses through the central longitudinal axis 108. Edge 376 has a slopedetermined by the difference between W₁ 312 and W₂ 328 and is asymmetric reflection of the slope of edge 346. Triangular side 338 isalso bounded by a first vertex 370 where edge 366 meets edges 368, 322,and 374, a second vertex 378 where edge 366 meets edge 376, and a thirdvertex 380 where edge 376 meets edges 374 and 326. Vertex 370 coincideswith a longitudinal edge 322 of hexagonal side 302, vertex 366 coincideswith a longitudinal edge 310 of square side 304, and vertex 380coincides with a longitudinal edge 326 of hexagonal side 318. In thismanner, the different geometries of first portion 104 and second portion106 are joined using an angled planar member 338 having vertices thatcoincide with longitudinal edges on first portion 104 or second portion106. Due to symmetry, corresponding planar members located oppositelyare similar.

The overall length of tubular body 102 along longitudinal axis 108 isshown as L₁ 386, the length of first end portion 104 is L₂ 388, giving aremainder length L₃ 390 corresponding to the length of second endportion 106. L₄ 392 is an outer length of middle portion 202 while L₅394 is an inner length of middle portion 202 corresponding to thelongitudinal extent of the triangular side members extending to a widersection of second end portion 106. Similarly, L₄ 392 corresponds to thelongitudinal extent of the triangular side members extending to anarrower section of second end portion 106. In one embodiment, L₁ 386 is13.600 centimeters (cm) in length, L₂ 388 is 3.800 cm in length, L₃ 390is 9.800 cm in length, L₄ 392 is 4.034 cm in length, and L₅ 394 is 2.951cm in length. In this manner, the ratio of the linear distance alongcentral axis 108 of L₂ to L₃ is 3.800 cm/9.800 cm=0.3878, and can rangefrom about 0.3500 to 0.4500. The maximum width W₁ 312 is dependent uponthe length of tubular body 102 so that the length L₁ 386 is at leastfive-times larger than width W₁ 312.

FIG. 4 shows an end view of tubular body 102 as viewed from the firstend of first tubular member 104 where first tubular member 104 is aregular, square polygon having equal length sides while second tubularmember 106 is not a regular, hexagonal polygon. In this case, the foursides (302, 304, 402, and 404) of first tubular member 104 meet at90-degrees at the juncture between adjacent sides. The six sides (314,316, 318, 406, 408, and 410) of second tubular member 106 for ahexagonal polygon that is compressed in a vertical direction so as toallow an approximately equal vertical height for edge 346 and horizontalwidth for edge 358. In this manner, the planar aspect presented by thehorizontal reflective internal surfaces (334, 336, 412, and 414) aresimilar in size to the vertical reflective internal surfaces (332, 416,338, and 418).

Dividing member 118 includes a plurality of radii (424, 426, 428, 430)emanating from a central portion of tubular body 102 along central axis108. In one embodiment, it is preferable for the distal ends of dividingmember 118 radii to meet the internal reflective surface of each sidenear a midpoint of the side. Since first portion 104 is a regular,square polygon, adjacent radii form right angles with each other whereangle 436 between radii (424, 426) is 90-degrees, and angle 438 betweenadjacent radii (424, 430) is 90-degrees so that the light receiving endof tubular body 102 is divided into square regions. Other configurationsare possible (not shown) including where the distal ends of radii (424,426, 428, and 430) are coincident with the corners of square first endportion 104 so that the light receiving end of tubular body 102 isdivided into triangular regions by vertical and horizontal divisions.The square or triangular regions form a cavity for separating theincoming beams (110, 112, 114, 116) prior to mixing.

In the case where coherent or non-dispersive light is received parallelto the central axis 108, it is desirable to reflect the incoming beamfrom a reflective surface in middle section 202 in order to avoid a “hotspot” in the homogeneous output of tubular body 102. Incoming coherentbeams are applied to the reflecting surfaces of middle portion 202 inorder to induce mixing and homogenization within second end portion 106.For example, a first coherent beam 448 is applied to a first pair ofreflecting surfaces (332 and 416), a second coherent beam 450 is appliedto a second pair of reflecting surfaces (334, 336), a third coherentbeam 452 is applied to a second pair of reflecting surfaces (338, 418),and a fourth coherent beam 454 is applied to a fourth pair of reflectingsurfaces (412, 414).

Each of these incoming coherent beams is applied to a reflecting surfacewithin middle portion 202 in order to initiate mixing. According to thisembodiment of tubular body 102, square first tubular member 104 has avertical height 460 and a horizontal width 462. Similarly, hexagonalsecond tubular member 106 has a vertical height 464 and a horizontalwidth 466 which are equal to each other. Longitudinal edge 320 meets andend portion of side 302 at vertex 350. Similarly, longitudinal edge 322meets an end portion of side 304 at vertex 370. Due to symmetry, alongitudinal edge 470 between second tubular member 106 sides 406 and408 meets first tubular member 104 side 402 at a vertex 472, and alongitudinal edge 476 between second tubular member 106 sides 408 and410 meets first tubular member 104 side 404 at a vertex 478.

FIG. 5 shows and end view of tubular body 102 as viewed from the firstend of first tubular member 104 where first tubular member 104 is aregular, square polygon having equal length sides while second tubularmember 106 is a regular, hexagonal polygon, also having equal lengthsides. In this manner, the planar aspect presented by the horizontalreflective internal surfaces (334, 336, 412, and 414) is different fromthe planar aspect presented by the vertical reflective internal surfaces(332, 416, 338, and 418).

According to this embodiment of tubular body 102, square first tubularmember 104 has a vertical height 502 and a horizontal width 504.Similarly, hexagonal second tubular member 106 has a vertical height 506and a horizontal width 508. Since first tubular member 104 is square,vertical height 502 is equal to horizontal width 504. However, sincesecond tubular member 106 is a regular hexagon, vertical height 506 isgreater than horizontal width 508. A result of having regular polygonalstructures such as the square first tubular member 104 and the hexagonaltubular member 106, the planar aspect presented by the horizontalreflective internal surfaces (334, 336, 412, and 414) is larger than theplanar aspect presented by the vertical reflective internal surfaces(332, 416, 338, and 418). Thus, when using a coherent incoming beam, thereflecting target is smaller for the vertical reflective internalsurfaces (332, 416, 338, and 418).

FIG. 6 shows and end view of tubular body 102 as viewed from the firstend of first tubular member 104 where first tubular member 104 is not aregular, square polygon yet still has equal length sides, while secondtubular member 106 is a regular, hexagonal polygon having equal lengthsides. In this manner, the planar aspect presented by the horizontalreflective internal surfaces (334, 336, 412, and 414) are similar to thevertical reflective internal surfaces (332, 416, 338, and 418).According to this embodiment of tubular body 102, first tubular member104 has a vertical height 602 and a horizontal width 604. Similarly,hexagonal second tubular member 106 has a vertical height 606 and ahorizontal width 608. Dividing member 118 includes a plurality of radii(610, 612, 614, 616) emanating from a central portion of tubular body102 along central axis 108. Since first portion 104 is not a regular,square polygon, adjacent radii do not form right angles with each otherwhere angle 618 between radii (610, 616) is acute, and angle 620 betweenadjacent radii (612, 614) is obtuse so that the light receiving end oftubular body 102 is divided into rhomboid regions similar to the shapeof the first portion 104.

FIG. 7 shows a flow diagram 700 indicating operations for a method ofproducing mixed and homogenized light from a plurality of incoming lightbeams each having a different wavelength using a light mixing andhomogenizing apparatus. The operations include receiving 702 a pluralityof incoming light beams into the divided light funnel first portion asdescribed in reference to FIG. 3. The method continues with an operationof reflecting 704 light off the interior surface of an undivided lightfunnel second portion. The method continues with mixing 706 the receivedlight beams within the light funnel second portion. The method continueswith homogenizing 708 the mixed light to produce a homogenized lightbeam having a substantially equal intensity distribution. Finally, themethod concludes with outputting 710 the mixed and homogenized light.

FIG. 8 shows a block diagram of a light mixing and homogenizing system800 that includes a plurality of light sources (802, 804, 806, and 808),a control unit 810, and a light mixing and homogenizing apparatus 100.Each light source outputs light of a different frequency or wavelength.For example, a first light source 802 outputs a first light beam 110having a first wavelength λ₁. A second light source 804 outputs a secondlight beam 112 having a second wavelength λ₂that is different from firstwavelength λ₁. A third light source 806 outputs a third light beam 114having a third wavelength λ₃ that is different from first wavelength λ₁,and second wavelength λ₁. Finally, a fourth light source 808 outputs afourth light beam 116 having a fourth wavelength λ₄ that is differentfrom first wavelength λ₁, second wavelength λ₂, and third wavelength λ₃.Although only four light sources are shown, the number of light sourcesis not limited to this example.

Control unit 810 outputs a plurality of control signals (812, 814, 816,and 818) in order to determine the intensity and wavelength of lightemitted from each light source. In this manner, a continuously variablehomogenized light beam may be produced having a color determined by thewavelength components of the plurality of incoming light beams. Forexample, control unit 810 asserts a first control signal 812 to firstlight source 802 in order to determine the intensity and wavelength offirst light beam 110 emitted from light source 802.

A light beam from a light source may be conducted in an optical conduitsuch as an optical fiber prior to introduction within light mixing andhomogenizing apparatus 100. The optical fiber may be considered as apart of the light source. Similarly, control unit 810 asserts a secondcontrol signal 814 to second light source 804 in order to determine theintensity and wavelength of second light beam 112 emitted from lightsource 804. Control unit 810 asserts a third control signal 816 tosecond light source 806 in order to determine the intensity andwavelength of second light beam 114 emitted from light source 806.Finally, control unit 810 asserts a second control signal 816 to secondlight source 808 in order to determine the intensity and wavelength ofsecond light beam 116 emitted from light source 808.

FIG. 9 shows an example of light intensity from a single optical fiberoutput where the light intensity profile varies across the diameter, ina direction perpendicular to the cross section of the fiber, in aGaussian distribution 902. FIG. 10 shows an example of light output fromthe light mixing and homogenizing apparatus producing a uniformintensity or top-hat profile 1002 across the span of the tubular bodyoutput.

FIG. 11 shows a plurality of incoming light sources (802, 804, 806, and808) producing a plurality of incoming light beams (110, 112, 114, and116) that are applied to a wider input 330 as a receiving end of lightmixing and homogenizing apparatus 100. Each incoming light beam has agaussian profile 902. Output beam 120 has a top-hat profile 1002 and isemitted from narrower output 340 as an outputting end of light mixingand homogenizing apparatus 100.

FIG. 12 shows the plurality of incoming light sources disposed within areceiving portion of the tubular body. A plurality of optical fibers(not shown) may be bundled together to receive the mixed and homogenizedlight from output 340. In this manner, the mixed and homogenized lightmay be applied evenly to each of the optical fibers in the bundle.Alternatively, the light from output 340 may be emitted directly intothe air or another medium.

FIG. 13 shows the ends of each light source (802, 804, 806, and 808) asinserted within the tubular body first end portion 104. As shown, thelight sources are inserted within first portion 104 a depth 1302 L_(I)which allows the light beam from each light source to be introduced intothe interior portion of tubular body 102 prior to mixing since theincoming light beams are separated from each other by dividing member118. Depth 1302 corresponds to the insertion depth of the light beamswithin first portion 104, and can vary from near the leading edge of theinterior surface of first portion 104 to about half the length 388 L₂ offirst portion 104.

Embodiments described above illustrate but do not limit the invention.It should also be understood that numerous modifications and variationsare possible in accordance with the principles of the present invention.Accordingly, the scope of the invention is defined only by the followingclaims.

1. A light mixing and homogenizing apparatus, comprising: a firsttubular member having a reflective interior surface and a polygonalcross section with a first maximum diameter and a first number of sides,the first tubular member having a first end and a second end, the firsttubular member first end being configured to receive a plurality ofincoming light beams; and a second tubular member having a reflectiveinterior surface and a polygonal cross section with a second maximumdiameter smaller than the first maximum diameter and a second number ofsides different from the first number of sides, the second tubularmember having a first end disposed adjacent to the first tubular membersecond end, the second tubular member having a second end configured tooutput a homogeneous light beam comprising a mixture of the plurality ofincoming light beams.
 2. The apparatus of claim 1, wherein alongitudinal edge is formed at the juncture of each pair of adjacentsecond tubular member sides, and wherein at least one of the secondtubular member first end longitudinal edges coincides with an endportion of a side of the first tubular member second end.
 3. Theapparatus of claim 1, further comprising: a plurality of planar membersconfigured to mate the first tubular member second end with the secondtubular member.
 4. The apparatus of claim 3, wherein the plurality ofplanar members form a funnel shape having a larger portion and a smallerportion, the larger portion of the funnel shape being disposed adjacentto the first tubular member second end.
 5. The apparatus of claim 3,wherein the plurality of planar members each has a triangular shapehaving at least one vertex coincident with one of a first tubular memberand a second tubular member longitudinal edge.
 6. The apparatus of claim3, wherein the planar members configured to mate the first tubularmember second end with the second tubular member comprise a tubular bodymiddle portion, the inner walls of the tubular body middle portionhaving a reflective surface, each planar member having a common edgewith the first tubular member.
 7. The apparatus of claim 1, wherein thefirst polygonal cross section has four sides.
 8. The apparatus of claim1, wherein the second polygonal cross section has six sides.
 9. Theapparatus of claim 1, further comprising: a dividing member disposedwithin the first tubular member first end configured to separate theplurality of incoming light beams from each other prior to mixing. 10.The apparatus of claim 9, wherein the dividing member radially separatesthe first tubular member first end into a plurality of regions about acentral longitudinal axis.
 11. The apparatus of claim 10, wherein thedividing member includes a plurality of radial members, each radialmember having a first end and a second end, each radial member first endbeing disposed towards a center portion of the first tubular member,each radial member second end being disposed at about the midpoint of afirst tubular member side.
 12. The apparatus of claim 10, wherein thedividing member separates the first tubular member first end into fourregions for receiving up to four incoming light beams.
 13. The apparatusof claim 1, wherein the ratio of a linear distance along the centralaxis of the first tubular member to a linear distance along the centralaxis of the second tubular member is between about 0.35 to 0.45.
 14. Alight mixing and homogenizing system, comprising: a plurality of lightsources, each light source providing a light beam having a uniquewavelength; a tubular body having a first end portion with a squarecross section and a second end portion with a hexagonal cross section,the first end portion being configured to receive the plurality of lightbeams, the tubular body second end portion being configured to output ahomogeneous light beam comprising a mixture of the incoming light beams,an interior portion of the tubular body having a highly reflectivesurface configured to reflect light from the plurality of incoming lightbeams causing a mixing and homogenizing of the plurality of light beams;and a divider disposed within the tubular body first end portionconfigured to separate the incoming light beams prior to mixing.
 15. Theapparatus of claim 14, further comprising: a control unit fordetermining a light intensity level for each of the plurality of lightsources.
 16. The apparatus of claim 15, wherein the control unitdetermines a wavelength of output light for each of the plurality oflight sources.
 17. The apparatus of claim 14, wherein the plurality oflight beams each have a gaussian profile.
 18. The apparatus of claim 14,wherein the output light beam has a top-hat profile.
 19. A method ofmixing and homogenizing a plurality of light beams, the methodcomprising: receiving the plurality of incoming light beams into adivided first portion of an optical funnel, each incoming light beamhaving a substantially unequal intensity distribution; mixing thereceived plurality of incoming light beams within an undivided secondportion of the optical funnel to produce a mixed light beam;homogenizing the mixed light beam to produce a homogenized light beamhaving a substantially equal intensity distribution; and outputting thehomogenized light beam.
 20. The method of claim 19, wherein mixing thereceived light beams within an undivided second portion of the opticalfunnel further comprises: reflecting each of the incoming light beamsfrom at least one interior surface of the optical funnel second portion.21. The apparatus of claim 19, wherein the optical funnel first portionhas a first diameter and the optical funnel second portion has a seconddiameter, the first diameter being larger than the second diameter.